In general I’d agree with Doug’s second list. The kit used during WWII would absolutely not be considered adequate today. However I would also include a snorkel, an emergency signaling device and a submersible pressure gauge and compass if your computer doesn’t have those functions.
You can’t dive (buy, rent or borrow equipment) until you have a minimum entry level communication. I’d suggest you do PADI Open Water Diver. Even if you live inland, they will find local diving in lakes or quarries for you to do. They will teach you all about equipment including choosing, fitting, use and maintenance on your course.
Happy diving!